1. Field of the Invention
This invention relates to an integrated controller, an integrated control system and a transmission controller, used for a steel manufacturing plant, a paper mill plant, a public utility system such as a water and sewage system, a manufacturing process of automobile industry and a petrochemical plant.
2. Description of the Background
Currently, three conventional control methods, which are a loop control, a sequence control and a computer control, are used in plants and manufacturing processes for various industrial fields.
The loop control, for example, is used for plants which need a repetitive control to keep a temperature of a certain portion at a predetermined value. A PID control and a feed back control are its representative samples. Since the loop control is a kind of control method used for a temperature control, it is said that a control cycle is, for example, from several hundred milliseconds to several seconds. The loop control is usually used for a petrochemical plant.
The sequence control, for example, is used in a situation that respective first, second and third manufacturing steps of an assembly line are managed sequencially. Accordingly, the sequence control is used in a case that only one output is needed for an appointed input, that is, in case of adopting a combination logic. The sequence control possesses a time factor, so-called sequence, in its control objectives. Since the sequence control is mainly used to control machinery, a control cycle is set to a relatively high speed, for example, from several milliseconds to several hundred milliseconds. The sequence control is widely used for systems for industries such as a paper mill plant, a public utility system such as a water and sewage system, and an assembly line of automobile industry.
The computer control is used in a condition that collected data and information are processed and analyzed. The computer control realizes a control based on an event as the event arises. As described above, a controlling target and a control cycle are generally different among a loop controller for the loop control, a programmable controller for the sequence control and a personal computer that runs software corresponding to OS to realize the computer control. Further, because a nature of a program is also different each other, programming languages expressing the program are different respectively. Accordingly, different platforms (hardware) and different programming languages are used for the respective controllers.
As described above, the loop control, the sequence control and the computer control are usually used as control methods. A control method suitable for each of control targets is selected and used so far. For example, the loop control is used for a temperature control of a food processing plant. The sequence control is used in a packaging stage for the processed foods.
On the other hand, users sometimes request to unify from the food processing stage to the packaging stage for the processed foods and to process the stages. That is, users want to manage the food processing stage and the packaging stage uniformly by being designed to unify a program of the loop control and a program of the sequence control.
However, a control cycle, a nature of a platform to be used and a programming language are different between the loop control and the sequence control. The same thing may occur in a case that a certain control other than the loop control and the sequence control is tried to be combined and unified.
Accordingly, since it requires a great deal of work to unify different controllers that realize respective different control, an approach to unify the different controllers is not thought positively so far.
Up to now, it requires a special apparatus such as a tag server that realizes a synchronous processing for data conversion, data communication and a control cycle in order to coordinate with the respective different controllers, thereby making a structure complicated and increasing a maintenance cost.
Further, it requires a large amount of initial cost to adopt such special apparatus in order to realize coordination among the different controllers, because it is needed to register various setting procedures concerning data conversion and data communication. Accordingly, it is difficult to install a new different controller and to change a program.
Accordingly, one object of this invention is to provide an integrated controller, an integrated control system and a transmission controller which may imaginarily integrate different controllers into a single controller by not simply coordinating with the different controllers.
Another object of this invention is to provide an integrated controller, an integrated control system and a transmission controller which may easily and positively integrate different controllers, reducing a special apparatus and work needed for integrating the different controllers.
The present invention provides an integrated controller, including a plurality of controllers, each of the controllers executing a different program, and an integrator configured to imaginarily integrate the controllers as a single controller.